Construction for vehicle brakes



July 2, 1935. E. R. EVANS CONSTRUCTION FOR VEHICLE BRAKES Original Filed 001;. '7, 1929 2 Sheets-Sheet l July 2, 1935. R EVANS 2,006,633

CONSTRUCTION FOR VEHICLE BRAKES I Original Filed Oct. 7, 1929 2 SheetsSheet 2 lllllllllllllllll l wf Patented July 2, 1935 PATENT OFFIOE 2,006,633 CON STRUOTION FOR VEHICLE BRAKES I Edwin R. Evans, Chicago, Ill.

Original application October 7, 1929, Serial No. 397,996. Divided and this application January 27, 1933, Serial No. 653,767

Claims. (01. 188- 78) 7 This invention relates to a new and improved construction for vehicle brakes, and more particularly to the construction of the brake parts carried upon or adjacent the vehicle wheels.

5 My invention relates to brake constructions of the type comprising a brake drum with means pivoted. within the drum and adapted to be expanded into engagement with the inner surface of the drum for braking purposes.

This application is a division of my application Serial No. 397,996 filed October 7, 1929.

It is an object of the present invention to provide a new and improved brake for vehicles.

It is also an object to provide an improved a pivot construction including means whereby the brake means may be adjusted and may have a reduced contact with the pivot means.

It is an additional object to provide a construction whereby the brake shoes may have substantially a point contact with the pivot and. whereby such contact maybe located upon the center line of the shoes.

Other and further objects will appear as the description proceeds.

I have shown certain preferred embodiments of my invention in the accompanying drawings, in which r 1 Figure 1 is a side elevation of one form of the construction showing it applied toa brake drum;

Figure 2 is a vertical section taken through the construction of Figure 1;

Figure 3 is a fragmentary section taken on line 33 of Figure 1; I

Figure 4 is a fragmentary section similar to Figure 3 but showing a modified form of construction;

Figure 5 is a view similar to Figure 3 showing a further modified form of centralizer construction;

Figure 6, is a fragmentary plan view of a further modified form of support for a centralizer; Figure 7 is a section taken on line 1--1 of Figure 6;

' Figure 8 is a fragmentary section showing the pivot construction;

Figure 9 is a fragmentary section showing the pivot construction and associated brake shoes; and

Figures 10 and 11 are views similar to Figure 9,

- but showing modified forms ofconstruction.

Referring first to Figures 1 and 2, the brake drum 2| is provided with an inturned flange 22 by which it may be suitably connected to the vehicle wheel. The back plate 23 is supported on a steering knuckle 24 and carries the brake mechanism. Thebearing bracket 25 is secured to the plate 23 by means of rivets 26 and is provided with an hexagonal opening through which I passes the pivot member 21. This pivot member, as best shown in Figure 9, is provided with 5 a reduced threaded portion 28 upon which is threaded a nut 29 having a bearing in an opening in the back plate 23. The pivot member 2'! is provided with a spring-pressed ball 30 carried in a bore drilled into the member, this ball be- 10 ing adapted to coact with grooves 3i broached or otherwise formed in the inner face of the nut 29. This is for the purpose of determining the extent of adjusting movement after the shoes have been brought to bear against the 15 brake drum by withdrawal of the member 21. p

The brake shoes 32 and 33. are provided with rounded ends 34 and 35 which fit into recesses machined in the'sides of the pivot member-21. These ends are rounded in a plane extending transversely or acrossv the outer face. of the brake shoe and are rounded so that the convex surface is toward the pivot member. These ends of the shoes pass through slots 35 formed in the side of the, bracket extension 31. The brake shoes are connected adjacent the pivot point by the cross spring 38, which retains the ends of the shoes in engagement with the pivot- Anti-rattler'springs 39 are provided, fitted about the flanges of the brake shoes and retained in place by cotter pins 40 passing through the supporting lugs 4| which are secured to the back plate 23. The lower ends of the brake shoes 32 and 33- are provided with the bearing plates 42 and 43. These bearing plates are shown as secured to the brake shoes by the rivets 44 and 45. j

The brake operating cam 46 is provided with barrel-shaped upper and lower portions fitting against, rounded portions formed in the adjacent edges of the bearing plates 42 and 43. The central portion of the cam member 46 is provided with extensionsflwhich serve to support the cam member between the bearing plates when in either the normal or the operating position,,by bearing against the inner surfaces of the inwardly extending arms of the bearing plates 42 and 43. The cam member 46 isprovided with the centrally located opening 48 which is drilled lengthwise of the cam. This 5 opening is preferably filled with a wick, or other lubricant holding substance, such as felt or the like, and radial openings 49 are drilled through the-barrel-shaped surfaces of the cam into the central bore 48. Additional wicks may 5 cent ends hooked into the back be provided in the openings 49. This arrangement serves to lubricate the surfaces which are in contact with the rounded surfaces of the wear platesand thus serves to both minimize wear and to reduce squeaks or noises.

The shoes 32 and 33 have the bearing plates.

42 and 43 held against the cam 46 bymeans ,of the springs II and 12, which have their; adiaplate 23. In the form of construction shown, the spring ll on the wrapping or self-energizing shoe 32is stronger than the spring 12' onth'e unwrapping shoe 33. By this means the braking efiect of the two shoes may be equalized to'a desired extent and also a' rapid release ofthe wrapping shoe assured.

The centralizer construction of Figure 2 is shown in greater detail in Figure 3. Here the back plate 23 is provided with thereces'sed portion 50 into which is welded the ber' 5i having a threaded interior threaded centralizer member 52.

tubular memto receive the This member s2 is shown as provided with the transverse slot of the -cehtralizer "I2 bears against the inner edge 56 of the flange of the brake shoe 32.. The conical end 55 isthreaded at a pitch similar to that of the threads of the bodyfportion oi the centralizer so that there;- is no lateral thrust upon the edge of the flange of the. brake shoe as the centralizer is threaded inwardly to force the brake shoeoutwardly into engagement with the brake drum 2|.

YA modified term of construction is shown in Figure 4, where the centralizer SI, ism'ovided with the smooth conical surface 58' which en gages an upturnedlip 58 on the'flange o! the brake shoe 68. This smooth/surface l8 the broad engagement on the lip us serve to -reduce any tendency 'to' thrust the brakeshoe laterally as the centralize! 81 is threaded mwardly. It will be noticed also that the angle of the conical face 58 issuch, and the axis or the cone is so placed, that the surface engages the brake shoe in a plane normal to that's! the adjusting "movement of the shoe- Thisiserves to further reduce any lateral thrustduring the adjustment. with the term of construction of Figure 3 it is unnecessary to coordinate the angle at which the centralizer is placed and the angle of theconical end, since the threads on the conical end will prevent lateral thrust and the angles may vary Iran those shown. 7 i

The form. of centralize!" shown in' l ig. 5 com sists of a hexagonal munber iilvvhichv is fitted through a hexagonal sleeve 82 carried by the back member 23. This member 6| is adiusted into and out of the sleeve 82 by means or the nut-63 and the adjustment'is hidlcatedby the spring-pressed ball 64, as previously described in connection with the other forms. hexagonal'member 6!. is provided with the inwardly inclined surface 5 which engages the inner edge of the flange 66 of the brake shoe 8']. It will be apparent that an outwardmo'v ement or the member 61 will serve to thrust the brakeshoe outwardly into engagement with the brake drum. Lateral movement of thebrake' shoe is limited by the sleeve 62 which would engage the a more simple and unitary structure. It will be noted from the plan, view of Figure .6 and section of Figure 7, that the thread?!) on the interior of thesleeve 68 is interrupted to form longitudinally extending recesses which would "coact with the spring-pressed ball contained in the centralizer' to be threaded into the sleeve 68.

In Figure 9, the brake shoes 32 and 33 are provided with the reduced rounded ends 13 and 14.. These ends are rounded on a circular arc struck from the points 15 and 16 as centers.

-The'se centers are located on the median line of .the two brake shoes.

It will be noted that the points of contact 11 and 18 with the bases of the slots 19 and formed in the pivot member 21, are not located on the median line of the shoes due to the angularity oi the base or the slot. It is desirable to have a point contact between the brake shoes and pivot to minimize wear and render the operation more easy and to allow self-alignment of the shoes.

I It may beconsidered desirable also to have the point .of contact located normally on the median line of the shoes, in which case the form of construction shown in Figure 10 may be used, where the extensions 8| and 82 formed on the brake shoes are not located on exactly the median:line of the shoes,- but are so located that the points of contact 83 and 84 between the rounded ends of the shoes and the bases of the grooves 'in the member are located on the median line of, the shoes. While this construe tion has the advantage'of so locating the contact point, "it has the disadvantage that it will be necessary to provide'right and left brake shoes, ialsqone forrn of shoe will not'serve upon. both sides of the pivot. The form of construction shown in Figurell differs from that shown in Figure 9 in that the pivot member 85 is carried in anintecral tubular extension formed on the back plate 81. The nut 88 threaded on the member 85 has a reduced portion 89 bearing against the shoulder forming the edge of the tubular portion 88.. The member 8B,".maybe circular in cross section since it will be prevented from rotating by the engagement of the .end portions 98 and 9| of the brake shoes in the slots 92 and 93 formed in the member 83. These extended portions 30 and II pass through slots formed in the tubular extension 86 and are thus prevented from displacement radially or the wheel. The nut is provided with the grooves 84, adapted to coac't with the springpressed ball carried in the bore 95. The form of construction of the pivot shown in Figure 8 diirers somewhat from that shown in the figures just described, in that the back plate 96 has an inturned flange 91 formed therein into which is rigidly secured a tubular member 98 which is shown as circular in cross section, al-

thoughit may be hexagonal in cross section or formed of a greater or less number of sides.

The sleeve 58 is held against rotation by being secured to the lntumed flange 91. The pivot member 99 fits'into the sleeve 98 and is provided with the slots "0 which are adapted to be locatedinwardly of the lateral openings I in the sleeve 98, which serve to admit the ends of the brake shoes. The nut I02 is threaded onto the reduced threaded extension I03 01 the pivot for member 99 and serves to move that member inwardly or outwardly of the sleeve 98.

In the use of the centralizers shown in Figures 1 to 4, it will be understood that the adjustment is had by first threading the centralizer in until the shoe is forced into engagement with the drum. The centralizer is then backed out until the desired clearance is secured. With a known pitch of the thread and a known number of clicks of the spring-pressed ball for each revolution of the centralizer, any desired clearance may be had by counting the clicks. The springpressed balls also serve as detents to prevent loss of adjustment after it has been secured.

The pivot adjustment is made in the same manner. The pivot member is drawn out until the shoes are forced against the drum and the pivot is then moved in a number of clicks to give the desired clearance. The detents are preferably similarly spaced on the centralizer and the pivot adjustment and the threads are the same or else the spacing and'threads are so related that the distances between detents on both centralizer and pivot represent the same amount of adjustment of the shoes.

While I have shown certain preferred embodiments of my invention by way of illustration, it is capable of further changes and modifications to meet varying conditions, and I contemplate such changes and modifications as come within the spirit and scope of the appended claims.

I claim:

1. In a brake construction, a brake pivot having shoe engaging surfaces thereon, a brake shoe having a convexly rounded end portion engaging a surface on the pivot, the contact surface on the shoe end being convex toward the surface on the pivot, the end portion being rounded in a plane extending transversely of the brake shoe.

2. In a brake construction, a brake pivot having inclined shoe engaging surfaces thereon, and a brake shoe having a rounded end portion engaging a surface on the pivot, the end portion being rounded in the plane of the engaging surfaces and making substantially a point contact with the surface.

.3. In a brake construction, a brake pivot having inclined shoe engaging surfaces thereon, and a brake shoe having a rounded end portion engaging a surface on the pivot, the end portion being rounded in the plane of the engaging surfaces and making substantially a point contact with the surface, the contact being located substantially in the median plane of the shoe.

4. In a brake construction, an adjustable pivot having an inclined shoe engaging surface, and a shoe having a convexly rounded surface engaging said surface, the surface being rounded convexly toward the pivot surface on a circular arc in a plane extending transversely of the brake shoe.

5. In a brake construction, an adjustable pivot having an inclined shoe engaging surface, and a shoe having a rounded surface engaging said surface, the surface being rounded on a circular arc in the plane of the shoe engaging surface, the'center of the are being laterally oifset whereby the point of engagement is located substantially upon the median plane of the shoe.

EDWIN R. EVANS. 

